80 People Came Into Contact With Ebola Patient Thomas Eric Duncan

A medical transport van moves past Texas Health Presbyterian Hospital Dallas where a patient has been diagnosed with the Ebola virus on September 30, 2014 in Dallas.

About 80 people came into contact with U.S. Ebola patient Thomas Eric Duncan or one of his family members before he was hospitalized, Dallas County health officials said Thursday.

However, not all of them were necessarily in close physical contact with the Liberian national, Dallas County's Health and Human Services director Zachary Thompson said. That number is in addition to the 12 to 18 people who had direct contact with Duncan, including some school-age children, Texas Gov. Rick Perry said Wednesday.

It's unclear if Duncan was already showing symptoms of the virus when he or his family in North Dallas came into contact with the estimated 80 people. But those contacts will be investigated, questioned and monitored to determine exactly how close they got.

Most, if not all of them, were notified Wednesday. Duncan, who was admitted to the hospital on Sunday after complaining of a fever and abdominal pain, remains in stable but serious condition. He's the first person to be diagnosed with Ebola in the U.S., and only began showing symptoms after arriving in the country on Sept. 20.

Separately, Texas health officials have ordered four family members who had contact with the Dallas Ebola patient to stay home and not have visitors to prevent the potential spread of disease.

The order, hand delivered to Thomas Eric Duncan's relatives Wednesday night by Texas Department of Health Services officials, legally requires the family to comply until at least Oct. 19, when the incubation period has passed and the family is no longer at risk of having the disease.

Ebola is not contagious until symptoms appear. The family members do not have symptoms at this time.

Duncan, 42, is the first person to be diagnosed with the killer disease in the United States. He traveled last month from his native Liberia and developed symptoms last week. He initially was sent home from a Dallas hospital and remained at home for two days while showing symptoms.